1. Field of the Invention
The present invention relates to an electromagnetic relay.
2. Description of the Related Art
In an electromagnetic relay including an electromagnet assembly and a contact section acting to open or close in accordance with the operation of the electromagnet assembly, both incorporated in a common base, it is known that the components of the electromagnet assembly and the components of the contact section are assembled or inserted into the mutually opposite sides of the base, for the purpose of ensuring an electrical insulation distance or clearance in terms of “creepage” (or a so-called creeping distance) between the electromagnet assembly and the contact section (see, e.g., Japanese Unexamined Patent Publication (Kokai) No. 11-213833 (JP-A-11-213833)). In the electromagnetic relay described in JP-A-11-213833, the base is provided with a first receptacle for receiving the electromagnet assembly, a second receptacle for receiving the contact section, and a partition wall defining the first and second receptacles on the mutually opposite sides of the partition wall. The partition wall of the base has a shape (referred to as “a crank shape” in JP'833) for regulating the direction of assembling of the electromagnet assembly into the first receptacle as to be reverse to the direction of assembling of the contact section into the second receptacle.
On the other hand, various electromagnetic relays have been developed in the field of, e.g., an application to switch a high voltage load, wherein each of a stationary contact member and a movable contact member, constituting the contact section, is provided at one longitudinal end with a board terminal connectable to a circuit board and at the other longitudinal end with a tab terminal connectable to a female-type terminal element. For example, Japanese Unexamined Patent Publication (Kokai) No. 2001-14996 (JP-A-2001-14996) describes an electromagnetic relay with a tab terminal, which is configured so that a stationary contact carried on the intermediate region of the stationary contact member and a movable contact carried on the intermediate region of the movable contact member are disposed at a location close to a yoke, the yoke being provided in the electromagnet assembly at the lateral side (or the radially outside) of a coil provided in the electromagnet assembly, and that a portion of an armature provided in the electromagnet assembly lies between the contact section (especially, the stationary and movable contacts) and the yoke. In the electromagnetic relay described in JP-A-2001-14996, an insulating wall extending from the base is inserted between the coil and the yoke in the electromagnet assembly, which are disposed to be overlapped on one another as seen in a radial direction of the coil, for the purpose of improving an insulating property between the coil and the contact section (the stationary and movable contacts).
Further, in an electromagnetic relay with a tab terminal, such as one described in JP-A-2001-14996, it has also been proposed to adopt the configuration in which the components of the electromagnet assembly and the components of the contact section are assembled onto the mutually opposite sides of the base in a way similar to JP-A-11-213833 (see, e.g., Japanese Patent No. 2893601 (JP-B-2893601)).
The electromagnetic relay described in JP-A-2001-14996 is configured so that the insulating wall is disposed between the coil and the yoke in the electromagnet assembly for improving the insulating effect between the electromagnet assembly and the contact section. As a result, there is a problem in that the external dimension of the electromagnetic relay as seen in a radial direction of the coil (or a height dimension) is increased, or that, under a given limitation on the external dimension, a space for disposing the coil on the base is reduced and, as a result, a magnetic attractive force is diminished. In contrast to this, in the electromagnetic relay described in JP-B-2893601, in which the components of the electromagnet assembly and the components of the contact section are assembled onto the mutually opposite sides of the base, it is possible to increase the creeping distance between the electromagnet assembly and the contact section, in comparison with the electromagnetic relay of JP-A-2001-14996, and therefore, no insulating wall is provided between the coil and the yoke in the electromagnet assembly. However, in the latter configuration, it is desired to further improve the insulating property between the electromagnet assembly and the contact section, particularly for an application to switch a high voltage load.